<template>
	<view style="position: fixed !important;top: 0 !important;bottom: 0 !important;left: 0 !important;right: 0 !important;z-index: 999;">
		<view class="signa">
			<view class="btn">
				<view hover-class="ubtn-hover" hover-stay-time="180" class="cancel-btn" @click="clear">
					重写
				</view>
				<view hover-class="ubtn-hover" hover-stay-time="180" class="save-btn" @click="save">
					确认
				</view>
			</view>
			<!-- bg-qianming -->
			<view :class="bgIndex === 1? 'bg-qianming' : 'bg-miaobian'" :style="{'width':width,'height':height}" class="canvas-view">
				<canvas class="canvas" disable-scroll="true" :style="{'width':width,'height':height}" canvas-id="designature"
					@touchstart="starts" @touchmove="moves" @touchend="end"></canvas>
			</view>
		</view>
	</view>
</template>

<script>
	import request from '../utils/request.js'
	export default {
		props: {
			bgIndex: {
				type: Number,
				default: 1
			}
		},
		data() {
			return {
				resultUrl: '',
				dom: null,
				line: [],
				width: '0px',
				height: '0px',
				radius: 0
			}
		},
		created() {
			uni.getSystemInfo({
				success: (res) => {
					this.width = res.windowWidth - 50 + 'px';
					this.height = res.windowHeight - 15 + 'px';
				}
			});
			this.dom = uni.createCanvasContext('designature', this);
		},
		methods: {
			end(e) {

			},
			distance(a, b) {
				let x = b.x - a.x;
				let y = b.y - a.y;
				return Math.sqrt(x * x + y * y);
			},
			starts(e) {
				console.log(e)
				this.line.push({
					points: [{
						time: new Date().getTime(),
						x: e.touches[0].x,
						y: e.touches[0].y,
						dis: 0
					}]
				})
				let currentPoint = {
					x: e.touches[0].x,
					y: e.touches[0].y
				}
				this.currentPoint = currentPoint
				this.drawer(this.line[this.line.length - 1])
			},
			moves(e) {
				console.log(e)
				let point = {
					x: e.touches[0].x,
					y: e.touches[0].y
				}
				this.lastPoint = this.currentPoint,
					this.currentPoint = point
				this.line[this.line.length - 1].points.push({
					time: new Date().getTime(),
					x: e.touches[0].x,
					y: e.touches[0].y,
					dis: this.distance(this.currentPoint, this.lastPoint)
				})
				this.drawer(this.line[this.line.length - 1])
			},
			drawer(item) {
				let x1, x2, y1, y2, len, radius, r, cx, cy, t = 0.5,
					x, y;
				var time = 0;
				if (item.points.length > 2) {
					let lines = item.points[item.points.length - 3];
					let line = item.points[item.points.length - 2];
					let end = item.points[item.points.length - 1];
					x = line.x;
					y = line.y;
					x1 = lines.x;
					y1 = lines.y;
					x2 = end.x;
					y2 = end.y;
					var dis = 0;
					time = (line.time - lines.time) + (end.time - line.time)
					dis = line.dis + lines.dis + end.dis;
					var dom = this.dom;
					var or = Math.min(time / dis * this.linePressure + this.lineMin, this.lineMax);
					cx = (x - (Math.pow(1 - t, 2) * x1) - Math.pow(t, 2) * x2) / (2 * t * (1 - t))
					cy = (y - (Math.pow(1 - t, 2) * y1) - Math.pow(t, 2) * y2) / (2 * t * (1 - t))
					dom.setLineCap('round')
					dom.beginPath();
					dom.setStrokeStyle('black')
					dom.setLineWidth(5)
					dom.moveTo(x1, y1);
					dom.quadraticCurveTo(cx, cy, x2, y2);

					dom.stroke();
					dom.draw(true)
				}

			},
			clear() {
				this.dom.clearRect(0, 0, 1000, 1000)
				this.dom.draw()
			},
			save() {
				var t = this;
				uni.canvasToTempFilePath({
					canvasId: 'designature',
					fileType: 'png',
					destWidth: 375,
					destHeight: 750,
					quality: 1, //图片质量
					success: (res)=> {
						console.log(res)
						wx.uploadFile({
							url: `${request.commonUrl}/file/uploadFile`,
							filePath: res.tempFilePath,
							name: 'file',
							formData: {
								'type': 3
							},
							success: (res) => {
								let resData = JSON.parse(res.data)
								if (resData.data) {
									this.$emit('save', resData.data)
								} else {
									uni.showToast({
										title: '图片返回失败',
										duration: 1000
									})
								}
							}
						})
						t.$emit('getImg', res.tempFilePath)
					},
					fail(e) {
						console.log(e)
					}
				}, this)
			}
		}
	}
</script>

<style scoped lang="scss">
	.signa {
		position: relative;
		overflow: hidden;
		background-color: #fbfbfb;
		height: 100vh;
		width: 100vw;
		
		.canvas-view {
			position: absolute;
			left: 45px;
		}

		.canvas {
			// background-color: #FFFFFF;
			background:rgba(255,255,255,0);/*关键点*/
			position: absolute;
			z-index: 9999;
			// left: 45px;
			left: 0;
		}

		.btn {
			height: 100vh;
			position: fixed;
			background-color: #007AFF;
			font-size: 30rpx;

			.cancel-btn {
				width: 42vh;
				position: fixed;
				left: 50rpx;
				border: 1px solid #AAAAAA;
				transform: rotate(90deg);
				color: #3961FA;
				margin-left: -21vh;
				margin-top: 21vh;
				height: 61rpx;
				line-height: 61rpx;
				border-radius: 3px;
				text-align: center;
				justify-content: center;
				background: #FFFFFF;
				z-index: 99999 !important;
			}

			.save-btn {
				position: absolute;
				z-index: 999;
				display: inline-flex;
				margin-top: 67vh;
				margin-left: -21vh;
				transform: rotate(90deg);
				background: #3961FA;
				width: 42vh;
				left: 50rpx;
				border-radius: 3px;
				color: #fff;
				height: 65rpx;
				line-height: 65rpx;
				text-align: center;
				justify-content: center;
			}
		}
	}
</style>
